See following slide for references

Plot and code inspired by http://www.stat.ubc.ca/~jenny/STAT545A/block17_colorsGgplot2Qualitative.html http://www.stat.ubc.ca/~jenny/notOcto/STAT545A/examples/gapminder/data/gapminderCountryColors.txt https://www.gapminder.org/

License https://creativecommons.org/licenses/by-nc/3.0/